1、Designation: C173/C173M 10aStandard Test Method forAir Content of Freshly Mixed Concrete by the VolumetricMethod1This standard is issued under the fixed designation C173/C173M; the number immediately following the designation indicates the yearof original adoption or, in the case of revision, the ye
2、ar of last revision. A number in parentheses indicates the year of last reapproval.A superscript epsilon () indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the Department of Defense.1. Scope*1.1 This test method covers determ
3、ination of the air contentof freshly mixed concrete containing any type of aggregate,whether it be dense, cellular, or lightweight.1.2 The values stated in either SI units or inch-pound unitsare to be regarded separately as standard. The SI units areshown in brackets. The values stated in each syste
4、m may not beexact equivalents; therefore, each system shall be used inde-pendently of the other. Combining values from the two systemsmay result in non-conformance with the standard.1.3 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theres
5、ponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.(WarningFreshhydraulic cementitious mixtures are caustic and may causechemical burns to skin and tissue upon prolonged exposure.2)2.
6、Referenced Documents2.1 ASTM Standards:3C29/C29M Test Method for Bulk Density (“Unit Weight”)and Voids in AggregateC31/C31M Practice for Making and Curing Concrete TestSpecimens in the FieldC138/C138M Test Method for Density (Unit Weight),Yield, and Air Content (Gravimetric) of ConcreteC143/C143M Te
7、st Method for Slump of Hydraulic-CementConcreteC172 Practice for Sampling Freshly Mixed ConcreteC173/C173M Test Method for Air Content of FreshlyMixed Concrete by the Volumetric MethodC231 Test Method for Air Content of Freshly Mixed Con-crete by the Pressure MethodC670 Practice for Preparing Precis
8、ion and Bias Statementsfor Test Methods for Construction Materials3. Significance and Use3.1 This test method covers the determination of the aircontent of freshly mixed concrete. It measures the air containedin the mortar fraction of the concrete, but is not affected by airthat may be present insid
9、e porous aggregate particles.3.1.1 Therefore, this is the appropriate test to determine theair content of concretes containing lightweight aggregates,air-cooled slag, and highly porous or vesicular natural aggre-gates.3.2 This test method requires the addition of sufficientisopropyl alcohol, when th
10、e meter is initially being filled withwater, so that after the first or subsequent rollings little or nofoam collects in the neck of the top section of the meter. Ifmore foam is present than that equivalent to 2 % air above thewater level, the test is declared invalid and must be repeatedusing a lar
11、ger quantity of alcohol. Addition of alcohol to dispelfoam any time after the initial filling of the meter to the zeromark is not permitted.3.3 The air content of hardened concrete may be eitherhigher or lower than that determined by this test method. Thisdepends upon the methods and amounts of cons
12、olidation effortapplied to the concrete from which the hardened concretespecimen is taken; uniformity and stability of the air bubbles inthe fresh and hardened concrete; accuracy of the microscopic1This test method is under the jurisdiction of ASTM Committee C09 onConcrete and Concrete Aggregates an
13、d is the direct responsibility of SubcommitteeC09.60 on Testing Fresh Concrete.Current edition approved July 1, 2010. Published August 2010. Originallyapproved in 1942. Last previous edition approved in 2010 as C173/C173M10.DOI: 10.1520/C0173_C0173M-10a.2Section on Safety Precautions, Manual of Aggr
14、egate and Concrete Testing,Annual Book of ASTM Standards, Vol 04.02.3For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM w
15、ebsite.1*A Summary of Changes section appears at the end of this standard.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.examination, if used; time of comparison; environmentalexposure; stage in the delivery, placement and consolidat
16、ionprocesses at which the air content of the unhardened concreteis determined, that is, before or after the concrete goes througha pump; and other factors.4. Apparatus4.1 Air MeterAn air meter consisting of a measuring bowland a top section (Fig. 1) conforming to the followingrequirements:4.1.1 The
17、measuring bowl and top sections shall be ofsufficient thickness and rigidity to withstand rough field use.The material shall not be attacked by high pH cement paste,deform when stored at high temperatures in closed spaces, orbecome brittle or crack at low temperatures. A watertight sealmust be obtai
18、ned when the top section is attached to themeasuring bowl.4.1.2 Measuring BowlThe measuring bowl shall have adiameter equal to 1 to 1.25 times the height and be constructedwith a flange at or near the top surface. Measuring bowls shallnot have a capacity of less than 0.075 ft32.0 L.4.1.3 Top Section
19、The top section shall have a capacity atleast 20 % larger than the measuring bowl and shall beequipped with a flexible gasket and a device to attach the topsection to the measuring bowl. The top section shall beequipped with a transparent scale, graduated in increments notgreater than 0.5 % from 0 a
20、t the top to 9 %, or more, of thevolume of the measuring bowl. Graduations shall be accurateto 60.1 % by volume of the measuring bowl. The upper end ofthe neck shall have a watertight cap that will maintain awatertight seal when the meter is inverted and rolled.4.2 FunnelA funnel with a spout of a s
21、ize permitting it tobe inserted through the neck of the top section and long enoughto extend to a point just above the bottom of the top section.The discharge end of the spout shall be so constructed thatwhen water is added to the container there will be a minimumdisturbance of the concrete.4.3 Tamp
22、ing RodA round, straight steel, high-densitypolyethylene, or other plastic rod of equal or greater abrasionresistance with a58 in. 16 m 6116 in. 2 mm diameter. Thelength of the tamping rod shall be at least 4 in. 100 mmgreater than the depth of the measuring bowl in which roddingis being performed,
23、but not greater than 24 in. 600 mm inoverall length (Note 1). The length tolerance for the tampingrod shall be 618 in. 4 mm. The rod shall have the tampingend or both ends rounded to a hemispherical tip of the samediameter as the rod.NOTE 1A rod length of 16 in. 400 mm to 24 in. 600 mm meets therequ
24、irements of the following: Practice C31/C31M, Test Method C138/C138M, Test Method C143/C143M, Test Method C173/C173M, and TestMethod C231.4.4 Strike-off BarA flat, straight steel bar at least18 by34by 12 in. 3 by 20 by 300 mm or a flat, straight high-densitypolyethylene bar, or other plastic of equa
25、l or greater abrasionresistance, at least14 by34 by 12 in. 6 by 20 by 300 mm.4.5 Calibrated CupA metal or plastic cup either having acapacity of or being graduated in increments equal to 1.00 60.04 % of the volume of the measuring bowl of the air meter.The calibrated cup is only to be used to add wa
26、ter when theconcrete air content exceeds 9 % or the calibrated range of themeter.4.6 Measuring Vessel for Isopropyl AlcoholA vessel witha minimum capacity of at least 1 pt 500 mL with graduationsnot larger than 4 oz 100 mL for measuring a quantity ofisopropyl alcohol.4.7 SyringeA rubber syringe havi
27、ng a capacity of at least2 oz 50 mL.4.8 Pouring Vessel for WaterA container of approxi-mately 1 qt 1 L capacity.4.9 Scoopof a size large enough so each amount ofconcrete obtained from the sampling receptacle is representa-tive and small enough so it is not spilled during placement inthe measuring bo
28、wl.4.10 Isopropyl AlcoholUse 70 % by volume isopropylalcohol (approximately 65 % by weight) (Note 2). OtherFIG. 1 Apparatus for Measuring Air Content of Fresh Concrete byVolumetric MethodC173/C173M 10a2foam-dispersing agents are permitted if tests demonstrate thatthe use of the agent does not change
29、 the indicated air content,in the amounts being used, by more than 0.1 % or if correctionfactors are developed similar to those in Table 1. When otherdispersing agents are used, a copy of the records documentingthe testing or calculations shall be available in the laboratory.NOTE 2Seventy percent is
30、opropyl alcohol is commonly available asrubbing alcohol. More concentrated grades can be diluted with water tothe required concentration.4.11 MalletA mallet (with a rubber or rawhide head) witha mass of approximately 1.25 6 0.5 lb 600 6 200 g.5. Calibration5.1 Calibrate the meter and calibrated cup
31、initially andannually or whenever there is reason to suspect damage ordeformation of the meter or calibrated cup.5.2 Determine the volume of the measuring bowl with anaccuracy of at least 0.1 % by determining the mass of waterrequired to fill it at room temperature and dividing it by thedensity of t
32、he water at the same temperature. Follow thecalibration procedure outlined in Test Method C29/C29M.5.3 Determine the accuracy of the graduations on the neckof the top section of the air meter by filling the assembledmeasuring bowl and top section with water to the level of themark for highest air co
33、ntent graduation.5.3.1 Add water in increments of 1.0 % of the volume of themeasuring bowl to check accuracy throughout the graduatedrange of air content. The error at any point throughout thegraduated range shall not exceed 0.1 % of air.5.4 Determine the volume of the calibrated cup using waterat 7
34、0 F 21.1 C by the method outlined in 5.2.Aquick checkcan be made by adding one or more calibrated cups of water tothe assembled apparatus and observing the increase in theheight of the water column after filling to a given level.6. Sampling6.1 Obtain the sample of freshly mixed concrete in accor-dan
35、ce with Practice C172. If the concrete contains coarseaggregate particles that would be retained on a 112-in.37.5-mm sieve, wet sieve a representative sample over a 1-in.25-mm sieve to yield somewhat more than enough material tofill the measuring bowl. The wet sieving procedure is describedin Practi
36、ce C172. Carry out the wet sieving operation with theminimum practicable disturbance of the mortar. Make noattempt to wipe adhering mortar from coarse aggregate par-ticles retained on the sieve.7. Procedure7.1 Rodding and TappingWet the inside of the measuringbowl and dry it to a damp but not shiny
37、appearance. Using thescoop described in 4.9, fill the measuring bowl with freshlymixed concrete in two layers of equal depth. While placing theconcrete in the measuring bowl, move the scoop around theperimeter of the measuring bowl opening to ensure an evendistribution of the concrete with minimal s
38、egregation. Rodeach layer 25 times uniformly over the cross section with therounded end of the rod. Rod the bottom layer throughout itsdepth. In rodding this layer, use care not to damage the bottomof the measuring bowl. For the upper layer, allow the rod topenetrate through the layer being rodded a
39、nd into the layerbelow approximately 1 in. 25 mm.After each layer is rodded,tap the sides of the measuring bowl 10 to 15 times with themallet to close any voids left by the tamping rod and to releaseany large bubbles of air that may have been trapped. Aftertapping the final layer, a slight excess of
40、 concrete,18 in. 3mm or less, above the rim is acceptable. Add or remove arepresentative sample of concrete if necessary to obtain therequired amount of concrete.7.2 Striking OffAfter rodding and tapping of the secondlayer, strike off the excess concrete with the strike-off bar untilthe surface is f
41、lush with the top of the measuring bowl. Wipethe flange of the measuring bowl clean.7.3 Adding Water and AlcoholWet the inside of the topsection of the meter, including the gasket. Attach the topsection to the measuring bowl and insert the funnel. Add atleast 1 pt 0.5 L of water followed by the sele
42、cted amount(Note 3) of isopropyl alcohol. Record the amount of isopropylalcohol added. Continue adding water until it appears in thegraduated neck of the top section (Note 4). Remove the funnel.Adjust the liquid level until the bottom of the meniscus is levelwith the zero mark. A rubber syringe is u
43、seful for this purpose.Attach and tighten the watertight cap.NOTE 3The amount of isopropyl alcohol necessary to obtain a stablereading and a minimum of foam at the top of the water column willdepend upon a number of factors. Many concretes made with less than 500lb/yd3300 kg/m3 of cement and air con
44、tents less than 4 % may requireless than 0.5 pt 200 mL of alcohol. Some high-cement mixes made withsilica fume that have air contents of 6 % or more may require more than3 pt 1400 mL of alcohol. The amount required will vary with theconcrete air content, the amount and type of air-entraining admixtu
45、re, thecement content and cement alkali content, and perhaps other factors.Generally, the amount of alcohol necessary can be established for givenmixture proportions and should not change greatly during the course of ajob.NOTE 4When, if ever, it is necessary to use more than 4 or 4.5 pt 2.0L of isop
46、ropyl alcohol, it may be necessary to restrict the amount of wateradded initially to avoid overfilling the meter. However, it is desirable toadd at least some water initially to aid in mixing the alcohol and limit thecontact of the concentrated alcohol with the top surface of the concrete.7.4 Displa
47、cing the Volume of Air in the Concrete SpecimenUsing These Procedures:7.4.1 Free the Concrete from the Measuring BowlQuickly invert the meter, shake the measuring bowl horizon-tally, and return the meter to the upright position. To preventthe aggregate from lodging in the neck of the unit, do not ke
48、epit inverted for more than5satatime. Repeat the inversion andshaking process for a minimum of 45 s and until the concreteTABLE 1 Correction for the Effect of Isopropyl Alcohol onC173/C173M Air Meter Reading70 % Isopropyl Alcohol UsedPints FluidOuncesLitres Correction, %A# 2.0 # 32 # 1.0 0.0B3.0 48
49、1.5 0.254.0 64 2.0 0.505.0 80 2.5 0.75ASubtract from final meter reading.BCorrections are applied only when 2.5 pt 1.25 L or more of isopropyl alcoholis used. The values given are for air meters that have a measuring bowl volume of0.075 ft32.1 L and a top section that is 1.2 times the volume of the meauring bowl.C173/C173M 10a3has broken free and the aggregate can be heard moving in themeter as it is inverted.7.4.2 RollingPlace one hand on the neck of the meter andthe other on the flange. Using
